Editing Decompression illness (section)

== Diagnosis ==
{{see also|Decompression sickness#Diagnosis|Air embolism#Diagnosis}}
Definitive diagnosis is difficult, as most of the signs and symptoms are common to several conditions and there are no specific tests for DCI. The dive history is important, if reliable, and the sequence and presentation of symptoms can differentiate between possibilities. Most doctors do not have the training and experience to reliably diagnose DCI, so it is preferable to consult a diving medicine specialist, as misdiagnosis can have inconvenient, expensive and possibly life-threatening consequences. Prior to 2000, there was a tendency to under-diagnose DCI, and as a result a number of cases did not get the treatment that could have produced a better result, while since 2000, there has been a swing to over-diagnosis, with consequent expensive and inconvenient treatments, and expensive inconvenient and risky evacuations that were not necessary.<ref name="Cronje 2014" /> The presence of symptoms of pneumothorax, mediastinal or interstitial emphysema would support a diagnosis of arterial gas embolism if symptoms of that condition are also present, but AGE can occur without symptoms of other lung overpressure injuries. Most cases of arterial gas embolism will present symptoms soon after surfacing, but this also happens with cerebral decompression sickness.<ref name="Cronje 2014" />

Numbness and tingling are associated with spinal DCS, but can also be caused by pressure on nerves (compression [[neurapraxia]]). In DCS the numbness or tingling is generally confined to one or a series of [[Dermatome (anatomy)|dermatomes]], while pressure on a nerve tends to produce characteristic areas of numbness associated with the specific nerve on only one side of the body distal to the pressure point.<ref name="Cronje 2014" /> A loss of strength or function is likely to be a medical emergency. A loss of feeling that lasts more than a minute or two indicates a need for immediate medical attention. It is only partial sensory changes, or paraesthesias, where this distinction between trivial and more serious injuries applies.<ref name="Cronje 2009" />

Large areas of numbness with associated weakness or paralysis, especially if a whole limb is affected, are indicative of probable brain involvement and require urgent medical attention. Paraesthesias or weakness involving a dermatome indicate probable spinal cord or spinal nerve root involvement. Although it is possible that this may have other causes, such as an injured intervertebral disk, these symptoms indicate an urgent need for medical assessment. In combination with weakness, paralysis or loss of bowel or bladder control, they indicate a medical emergency.<ref name="Cronje 2009" />